Improvement in bit-stocks



NAPETERS. PHOTO-LITHOGRAHHER, WASHINGTONY D C am einer taf-,cttw

can n H; L ARK,` rrr Tsrrn L D, M A I N E.Y

o LettesPatent No. `-105,906, dated August 2, 1870.v

IMPROVEMENT BIT-s'rocxs.

The Schedule referred to in these Letten-:Patent andmaking part of the sama To all whom it mayconce/ra:`

' Bei'i-knownthat I, CHARLEsH. CLARK, of Pittsfield, in the county of Somerset and StateofMa-ine, haveinveuted afncw anduseful improved Brace for Bitsyand I do hereby 'declare the following toibe a full, clear, and exact ,descriptiony thereof', suioient to enable those skilled in theart to which my invention appertainsvto fullyunderstand andr tomake and use the same, referencebeingthad to the accompanying drawing. forming 'part of this specification, and in which-Lf o 'fr i `Figure 1 is a top viewof the brace; v ,Figure 2, aview, showing one side thereof and s :Figure 3,-a side view, partly in section, on the line a; x, lig. 1, and wheel. r o l a a The subject 'oi' this invention is a brace for use with drilling and boring -fbits, provided with adjustable gearing, whereby the bit can be driven .at diiierent rates'of speed, and also having an extensible stock and craikifor. increasing the. power, and with a left handle, which can be-detached'when it is desired to use the brace near `a partition or other obstruction.

` "The invention consists in the construction, arrangement; and combination of parts, as hereinaftende-v scribed and claimed,` o

4,Similar letters of reference indicate like parts in'the several figures. o

Referrin'g'to the,drar.v`ing-A 1 A represents aframe, which will generally be vmade of cast-iron, inthe form shown, and'with a cylindrical shan-k, aa`nd bearings, b .c,for therotary bit-holder1 d, whichisfkeptinplaceby'acollar, e.

fIn the outerend of the bit-holder is a socket, f, for the shanki of the bit. y v

gris a pinion, cast or provided with a tubular portin, h, which Slideson the holder but is prevented from rotating thereonlby the .catch t', pivoted in a recess in the tubular portion h, and entering aA groove, j, in the bit-holder,` in" which position it is' held by the pressure of a sprin`g,k.y 1 l s 4 rlhere are several `notches in the bottom of the groove j, into either of whiclrt-,he catch will. enter and hold the'pinion in place. "By/pressure on the outer' endofthe catch itis disengaged from the notch,;and then the pinion canib'e adjusted to another point.

t isaShOrt'round pin, projeotingfromfthe part b of frameA.,` o ,o o ,y

On thisI pin is fitted to revolve a gear-wheel, which, in this example, `is composed `of' three concentric toothed rims, m 4a o, held together lby crossed brace's p. `In practice, these rims and'L braces will be all cast together.` y Y y showing the inner face of the drive- It is obvious that a solid wheel may be employed, butthe` one 'described has the advantage of lightness. y

One or more `washers may be placed on the pin l, between the wheel and'frame.

.It will be seen that the pinion may be adj usted uto engage with either rim m Aa o, and consequentlythe motion of the c rank may be multiplied, to rotate the bit fast or slow, according to the nature of the work, or the material operated'upon.

o On the outer face ofthe gear-wheel are twoprol jecting pins, q 1, one of which is provided with a screw-thread. o

These pins serveas guides for the crank-handle s, which is slotted, as shown, to receive the pins.

This handle can he lengthened or shortened, as desired, according to-the power to be exerted, and it is ixed,`when adjusted, by means of the thumb-nut t, screwed onto one of the pins, r l

That the stock a may be adjusted according as the crank-handle is lengthened and shortened, it is secured toa tubular shank, e, which receives the shanka', and is adjustablethereon, being provided with a thumb-screw, w, which enters a groove in the part a. l Y

`By this `construction the stock may be lengthened or shortened, and fixed at any point, but is rendered incapable of rotation on the shank.

o The left handle Vy is detachably secured to the frame A, so that it can be removed when itis required to use the brace in close proximity to apartition or other impediment of the kiud.-

, In this example, the handle is provided with a threaded shank, whichscrews into the fratrie A.

lVhen the gear-wheel and pinion are toothed, as in this instance, the bit-holder 1s rotated once at eacln revolhtion of the crank, when the inner rim-is engaged,'twice when the'middle rim is used, and three times withv the outer circle. 4

`I reserve the right of employing any number of rims, and providing any number and size of teeth.

By lengthening the handle, the power exerted is made much more effective, whichl is important when drilling hard metals. i

The stock is not only niade'extensiblato accommodate the lengthening of the crank-handle, .but for an additional purpose-the factl that, when the stock is lengthened, it is easier to make a true bore.

The brace as thus constructed is very useful for drilling in metals, as well as boringwood, because the speed and power can be so readily-multiplied and adapted to the nature of the work and material, and the size of the bit.

Having thus described my invention, A What l claim as new, and desire to secure by Letters Patent, is

structed and arranged to operate substantially as herein described.

In testimony that I claim the above, have hereunto subscribed my name in presence of' two wit- HQSSGS.

Witnesses R. M. MANSUR, H. B. LILLEY.

CHARLES :EL CLARK. 

